A GPS for finding the route to transplantation for the sensitized patient:

Post-listing survival for highly sensitised patients on the UK kidney transplant waiting list: a matched cohort analysis

BACKGROUND

More than 40% of patients awaiting a kidney transplant in the UK are sensitised with human leucocyte antigen (HLA) antibodies. Median time to transplantation for such patients is double that of unsensitised patients at about 74 months. Removing antibody to perform an HLA-incompatible (HLAi) living donor transplantation is perceived to be high risk, although patient survival data are limited. We compared survival of patients opting for an HLAi kidney transplant with that of similarly sensitised patients awaiting a compatible organ.

METHODS

From the UK adult kidney transplant waiting list, we selected crossmatch positive living donor HLAi kidney transplant recipients who received their transplant between Jan 1, 2007, and Dec 31, 2013, and were followed up to Dec 31, 2014 (end of study). These patients were matched in a 1:4 ratio with similarly sensitised patients cases listed for a deceased-donor transplant during that period. Data were censored both at the time of transplantation (listed only), and at the end of the study period (listed or transplant). We used Kaplan-Meier curves to compare patient survival between HLAi and the matched cohort.

FINDINGS

Of 25 518 patient listings, 213 (1%) underwent HLAi transplantation during the study period. 852 matched controls were identified, of whom 41% (95% CI 32-50) remained without a transplant at 58 months after matching. We noted no difference in survival between patients who were in the HLAi group compared with the listed only group (log rank p=0·446), or listed or transplant group (log rank p=0·984).

INTERPRETATION

Survival of sensitised patients undergoing HLAi in the UK is comparable with those on dialysis awaiting a compatible organ, many of whom are unlikely to be have a transplant. Choosing a direct HLAi transplant has no detrimental effect on survival, but offers no survival benefit, by contrast with similar patients studied in a North American multicentre cohort.

FUNDING

UK National Health Service Blood & Transplant and Guy's & St Thomas' National Institute for Health Research Biomedical Research Centre.

Translational research in kidney transplantation and the role of patient engagement

Background

Translational research is an evolving discipline that is intended to bridge the gaps between basic science research, clinical research, and implementation in clinical practice. It is a fluid, multidirectional process that requires strong interdisciplinary collaboration to produce research that is relevant to end-users.

Purpose of this review

This review summarizes current perspectives on translational research and outlines its relevance and importance to kidney transplantation research.

Sources of information

Sources of information used for this review include published reports, articles, and research funding websites.

Findings

Tissue typing is used as an in-depth example of how translational research has been applied in the field of kidney transplant medicine, and how it has resulted in successful implementation of diagnostic and management options for sensitized individuals undergoing kidney transplantation. The value of actively involving kidney transplant stakeholders (patients, caregivers, and clinicians) in setting research priorities and determining relevant outcomes for future investigation is also discussed.

Limitations

This is a narrative review of the literature which has been partly influenced by the perspectives and experiences of its authors.

Implications

Translational and patient-oriented research practices should be incorporated into future research endeavours in the field of kidney transplantation in order to create beneficial change in clinical practice and improve patient outcomes.

What was known before

Translational research which engages patients in the investigative process can enhance the likelihood that medical discoveries will have a meaningful impact at the bedside.

What this adds

This article applies current perspectives on translational research and patient engagement to the field of kidney transplantation, illustrating how these approaches have led to significant advancements in the field. It provides further justification for deliberate, targeted efforts to cross-collaborate and incorporate the patient voice into kidney transplant research.

Impact of donor-specific antibodies in reconstructive transplantation

For many devastating injuries and tissue defects where conventional reconstruction is not possible, reconstructive transplantation such as hand and face transplantation has become a viable alternative. This novel approach allows for improved restoration of appearance, anatomy and function not feasible by other available treatment options. However, clinical management of these injuries prior to transplantation frequently requires multiple blood transfusion or skin grafts resulting in the formation of alloantibodies (anti-HLA IgG Abs) and a high degree of sensitization. The role of donor-specific antibodies (DSA) and mechanisms of antibody-mediated rejection (AMR) in reconstructive transplantation are still largely unknown. Thus there is an imminent need to develop a better understanding of the mechanisms related to DSA and AMR after reconstructive transplantation. In this review, we will define the role of DSA and mechanisms of AMR in reconstructive transplantation and compare them to established measures and treatment concepts in solid organ transplantation.

Transplanting the highly sensitized patient: trials and tribulations

PURPOSE OF REVIEW

Humoral sensitization to antigens of the human leukocyte antigen and ABO systems remains one of the largest barriers to further expansion in renal transplantation. This barrier translates into prolonged waiting time and a greater likelihood of death. The number of highly sensitized patients on the renal transplant waiting list continues to increase. This review focuses on the options available to these patients and speculates on future directions for incompatible transplantation.

RECENT FINDINGS

Desensitization protocols (to remove antibodies), kidney-paired donation (to circumvent antibodies) or a hybrid technique involving a combination of both have broadened the access to transplantation for patients disadvantaged by immunologic barriers. However, the risk of antibody-mediated rejection may be increased and warrants caution. Technical advances in antibody characterization using sensitive bead immunoassays and the C1q assay and therapeutic modalities such as complement inhibitors and proteasome inhibitors have been used to avoid or confront these antibody incompatibilities.

SUMMARY

A growing body of knowledge and literature indicates that these diagnostic and therapeutic modalities can facilitate a safer and more successful treatment course for these difficult-to-treat patients. Rigorous investigations into newer interventions will help in broadening the options for these patients and also expand the living donor pool.

Transplantation of the sensitized patient: histocompatibility testing

A component necessary for successful transplantation of the sensitized patient is timely and high quality support from the histocompatibility laboratory that helps guide selection of the best route to transplantation and the clinical care of the patient. Responsibilities of the laboratory include risk assessment, HLA typing, and accurate antibody characterization.